90 DISEASES OF THE HEART 



the hypertrophied heart eventually growing weaker and 

 becoming distended by the abnormally increased blood 

 pressure. It may also develop in an acute form after acute 

 diseases of the lungs, as the circulation through the right 

 heart is greatly interfered with. 



Necropsy.— In both hypertrophy and dilatation the heart 

 is enlarged, in hypertrophy the increase in the thickness of 

 the walls, in dilatation in an enlargement of its cavities. 



(a) True hypertrophy of the heart appears in several 

 forms, depending upon whether it is general or local, i. e., 

 involving a whole ventricle, or circumscribed affecting only 

 some of the papillary muscles. The left heart is most fre- 

 quently affected. In hypertrophy the shape of the heart 

 will vary. When the left heart is involved it appears elon- 

 gated, cylindrical; when the right heart, it is natter and 

 broader than normal. If the whole heart is hypertrophied 

 it assumes a round or oval form and is increased in size. The 

 walls are usually two or three times the normal thickness, 

 the muscles firmer, tougher, darker red in color, and the inter- 

 stitial connective tissue occasionally shows marked prolifera- 

 tion. Sometimes areas of fatty degeneration are noted on the 

 surface. 



(b) In dilatation of the heart the cavities are found much 

 larger than normal, and the walls thinner and weaker. In 

 the active form of dilatation the walls are stronger than in 

 the passive where they are relaxed and distended. Dilatation 

 appears oftener in the right heart than in the left. The 

 structure of the muscles may be normal. Usually, however, 

 the organ is anemic, friable, the musculature yellowish- 

 brown in color, often very thin, and due to a complete atrophy 

 of the muscle, in some areas the wall is almost transparent. 



Symptoms.— In true hypertrophy of the heart, especially 

 compensatory, the development is often so gradual that it 

 may exist for a long period without producing marked symp- 

 toms. In severe cases, when accompanying other diseases, it 

 is characterized by a strong, full pulse, very loud, clear heart 

 sounds, and an increase in the area of cardiac dulness. Due 

 to the coexistence of dilatation the symptoms which charac- 

 terize hypertrophy are rarely noted in practice. The most 



